No.

Wind speed

Descriptive term

Effects observed

km/h

knots

On land

On sea

0

<1

<1

Calm

Calm; smoke rises vertically

Sea like a mirror

1

1-5

1-3

Light air

Smoke drift indicates wind direction

Ripples are formed but without foam crests

2

6-11

3-6

Light breeze

Leaves rustle; wind vanes move

Small wavelets; crests have a glassy appearance and do not break

3

12-19

6-10

Gentle breeze

Leaves, small twigs in constant motion

Large wavelets; crests begin to break; foam of glassy appearance

4

20-28

11-15

Moderate breeze

Dust, leaves and loose paper raised from ground; small branches move

Small waves, becoming longer; fairly frequent white horses

5

29-38

16-21

Fresh breeze

Small trees in leaf begin to sway

Moderate waves; many white horses formed

6

39-49

21-27

Strong breeze

Larger tree branches in motion; whistling heard in wires

Large waves begin to form; white foam crests everywhere (probably some spray)

7

50-61

27-33

Near gale

Whole trees in motion; difficulty in walking

Sea heaps up; white foam from breaking waves begins to be blown in streaks

8

62-74

33-40

Gale

Twigs and small branches broken off trees; walking impeded

Moderately high waves of greater length; foam is blown in well-marked streaks

9

75-88

41-48

Strong gale

Slight damage to structures; slates blown from roofs

High waves; crests of waves begin to topple, tumble and roll over

10

89-102

48-55

Storm

Trees broken or uprooted; considerable damage to structures

Very high waves with long over-hanging crests; on the whole the surface of the sea takes on a white appearance; the tumbling of the sea becomes heavy and shock- like; visibility affected

11

103-117

56-63

Violent storm

Usually widespread damage

Exceptionally high waves; visibility affected

12

>117

>63

Hurricane

Usually widespread damage

The air is filled with foam and spray; sea completely white with driving spray; visibility seriously affected

No.

Central pressure (mbar)

Winds (km/h)

Surge (m)

Damage

On land

At sea

1

>980

120-150

1.2-1.5

Damage to shrubbery, trees, foliage and poorly anchored mobile homes. Some damage to signs.

Some low-lying coastal roads flooded. Limited damage to piers and exposed small craft.

2

965-979

151-175

1.6-2.4

Trees stripped of foliage and some of them broken down. Exposed mobile homes suffer major damage. Poorly constructed signs are severely damaged. Some roofing material ripped off; windows and doors might be affected.

Coastal roads and escape routes flooded 2-4 hours before hurricane centre arrives. Piers suffer extensive damage and small unprotected craft are torn loose. Some evacuation of coastal areas is necessary.

3

945-964

175-210

2.5-3.6

Foliage stripped from trees and many blown down. Great damage to roofing material, doors and windows. Some small buildings are structurally damaged.

Serious coastal flooding and some coastal buildings may be damaged. Battering of waves might affect large buildings, but not severely. Coastal escape routes cut off 3-5 hours before hurricane centre arrives. Flat terrain 1.5 m or less above sea level is flooded as far inland as 13 km. Evacuation of coastal residents for several blocks inland may be necessary.

4

920-944

211-250

3.7-5.5

Shrubs, trees and signs are all blown down. Extensive damage to roofing materials, doors and windows. Many roofs on smaller buildings may be ripped off. Mobile homes destroyed.

Flat land up to 3 m above sea level might be flooded to 10 km inland. Extensive damage to the lower floors of buildings near the coast. Escape routes cut 3-5 hours before hurricane centre passes. Beaches suffer major erosion, and evacuation of homes within 500 m of coast may be necessary.

5

<920

>250

>5.5

Increase on the extensive damage of the previous level. Glass in windows shattered and many structures blown over.

Lower floors of structures within 500 m of coast extensively damaged. Escape routes cut off 3-5 hours before hurricane centre arrives. Evacuation of low lying areas within 8-16 km of coast may be necessary.

Basin and stage

Jan.

Feb.

Mar.

Apr.

May

June

July

Aug.

Sep.

Oct.

Nov.

Dec.

Annual

North Atlantic

Tropical storms

*

*

*

*

0.1

0.4

0.3

1.0

1.5

1.2

0.4

*

4.2

Hurricanes

*

*

*

*

*

0.3

0.4

1.5

2.7

1.3

0.3

*

5.2

Tropical storms and hurricanes

*

*

*

*

0.2

0.7

0.8

2.5

4.3

2.5

0.7

0.1

9.4

Eastern north Pacific

Tropical storms

*

*

*

*

*

1.5

2.8

2.3

2.3

1.2

0.3

*

9.3

Hurricanes

*

*

*

*

0.3

0.6

0.9

2.0

1.8

1.0

*

*

5.8

Tropical storms and hurricanes

*

*

*

*

0.3

2.0

3.6

4.5

4.1

2.2

0.3

*

15.2

Western north Pacific

Tropical storms

0.2

0.3

0.3

0.2

0.4

0.5

1.2

1.8

1.5

1.0

0.8

0.6

7.5

Typhoons

0.3

0.2

0.2

0.7

0.9

1.2

2.7

4.0

4.1

3.3

2.1

0.7

17.8

Tropical storms and typhoons

0.4

0.4

0.5

0.9

1.3

1.8

3.9

5.8

5.6

4.3

2.9

1.3

25.3

Southwest Pacific and Australian area

Tropical storms

2.7

2.8

2.4

1.3

0.3

0.2

*

*

*

0.1

0.4

1.5

10.9

Typhoons/cyclones

0.7

1.1

1.3

0.3

*

*

0.1

0.1

*

*

0.3

0.5

3.8

Tropical storms and typhoons/cyclones

3.4

4.1

3.7

1.7

0.3

0.2

0.1

0.1

*

0.1

0.7

2.0

14.8

Southwest Indian Ocean

Tropical storms

2.0

2.2

1.7

0.6

0.2

*

*

*

*

0.3

0.3

0.8

7.4

Cyclones

1.3

1.1

0.8

0.4

*

*

*

*

*

*

*

0.5

3.8

Tropical storms and cyclones

3.2

3.3

2.5

1.1

0.2

*

*

*

*

0.3

0.4

1.4

11.2

North Indian Ocean

Tropical storms

0.1

*

*

0.1

0.3

0.5

0.5

0.4

0.4

0.6

0.5

0.3

3.5

Cyclones^b

*

*

*

0.1

0.5

0.2

0.1

*

0.1

0.4

0.6

0.2

2.2

Tropical storms and cyclones^b

0.1

*

0.1

0.3

0.7

0.7

0.6

0.4

0.5

1.0

1.1

0.5

5.7

No.

Descriptive term

Description^b

Acceleration(cm s^-2)

I

Imperceptible earthquakes.

Not felt. Marginal and long-period effects of large

<1

II

Very slight placed.

Felt by persons at rest, on upper floor, or favourably

1-2

III

Slight

Felt indoors. Hanging objects swing. Vibration like passing of light trucks. Duration estimated. May not be recognised as an earthquake.

2-5

IV

Moderate

Hanging objects swing. Vibration like passing of heavy trucks or sensation of a jolt like a heavy ball striking the walls. Standing motor cars rock. Windows, dishes, doors rattle. Glasses clink, crockery clashes. In upper range of IV, wooden walls and frames creak.

5-10

V

Rather strong

Felt outdoors; direction estimated. Sleepers waken. Liquids disturbed, some spilled. Small unstable objects displaced or upset. Doors swing, close, open. Shutters, pictures move. Pendulum clocks stop, start, change rate.

10-20

VI

Strong

Felt by all. Many frightened and run outdoors. People walk unsteadily. Dishes, glassware broken. Knick-knacks, books, off shelves. Pictures off walls. Furniture overturned or moved. Weak plaster, masonry D cracked. Small bells ring. Trees shaken.

20-50

VII

Very strong

Difficult to stand. Noticed by motor car drivers. Hanging objects quiver. Furniture broken. Damage to masonry D, including cracks. Weak chimneys broken at roof line. Fall of plaster, loose bricks, stones, tiles, cornices. Some cracks in masonry C. Waves on ponds: water turbid with mud. Small slides and caving in along sand or gravel banks. Large bells ring. Concrete irrigation ditches damaged.

50-100

VIII

Destructive

Steering of motor cars affected. Damage to masonry C: partial collapse. Some damage to masonry B, none to masonry A. Fall of stucco, some masonry walls. Twisting, fall of chimneys, factory stacks, monuments, towers, elevated tanks. Frame houses move on foundations if not bolted down; loose panel walls thrown out. Decayed piling broken off. Branches broken from trees. Changes in flow or temperature of springs and wells. Cracks in wet ground, on steep slopes.

100-200

IX

Devastating

General panic. Masonry D destroyed; masonry C heavily damaged, sometimes with complete collapse; masonry B seriously damaged. Frame structures, if not bolted, shifted off foundations. Frames cracked. Serious damage to reservoirs. Underground pipes broken. Conspicuous cracks in ground. In alluviated areas sand and mud ejected, earthquake fountains, sand craters.

200-500

X

Annihilating

Most masonry and frame structures destroyed with their foundations. Some well-built wooden structures and bridges destroyed. Serious damage to dams, dykes, and embankments. Large landslides. Water thrown on banks of canals, rivers, lakes, etc. Sand and mud shifted horizontally on beaches and flat land. Rails bent slightly.

500-1000

XI

Disaster

Rails bent greatly. Underground pipelines completely out of service.

1000-2000

XII

Major Disaster

Damage nearly total. Large rockmasses displaced. Line of sight and level distorted. Objects thrown into the air.

>2000

^aReproduced from reference 1 by permission of the publisher.

^bMasonry A:

Good workmanship, mortar and design; reinforced, especially laterally, and bound together using steel, concrete, etc.; designed to resist lateral forces.

Masonry B:

Good workmanship and mortar; reinforced, but not designed in detail to resist lateral forces.

Masonry C:

Ordinary workmanship and mortar; no extreme weaknesses like failing to tie in at corners, but neither reinforced nor designed against horizontal forces.

Masonry D:

Weak materials, such as adobe; poor mortar; low standards of workmanship; weak horizontally.

Grade

Description of damage

0

None

Building is intact.

1

Negligible

Hairline cracks in walls or structural members: no distortion of structure or detachment of external architectural details.

2

Light

Building continues to be habitable; repair not urgent. Settlement of foundations, distortion of structure and inclination of walls are not sufficient to compromise overall stability.

3

Moderate

Walls out of perpendicular by 1-2°, or substantial cracking has occurred to structural members, or foundations have settled during differential subsidence of at least 15 cm: building requires evacuation and rapid attention to ensure its continued life.

4

Serious

Walls out of perpendicular by several degrees; open cracks in walls; fracture of structural members; fragmentation of masonry; differential settlement of at least 25 cm compromises foundations; floors may be inclined by 1-2°, or ruined by soil heave; internal partition walls will need to be replaced; door and window frames too distorted to use; occupants must be evacuated and major repairs carried out.

5

Very serious

Walls out of plumb by 5-6°; structure grossly distorted and differential settlement will have seriously cracked floors and walls or caused major rotation or slewing of the building (wooden buildings may have detached completely from their foundations). Partition walls and brick infill will have at least partly collapsed: roof may have partially collapsed; outhouses, porches and patios may have been damaged more seriously than the principal structure itself. Occupants will need to be rehoused on a long-term basis, and rehabilitation of the building will probably not be feasible.

6

Partial collapse

Requires immediate evacuation of the occupants and cordoning off the site to prevent accidents from falling masonry.

7

Total collapse

Requires clearance of the site.

Degree of slope failure

Probability of slope failure in earthquake ground-shaking intensity

VI

VII

VIII

IX

X

Light

40%

25%

15%

10%

5%

Moderate

30%

30%

35%

30%

20%

Heavy

25%

35%

40%

40%

35%

Severe

5%

10%

10%

15%

30%

Catastrophic

0%

0%

0%

5%

10%

Intensity

Run-up height (m)

Descriptive term

Description

I

0.5

Very light

Waves so weak as to be perceptible only on tide gauge records.

II

1

Light

Waves noticed by those living along the shore and familiar with the sea. On very flat shores generally noticed.

III

1

Rather strong

Generally noticed. Flooding of gently sloping coasts. Light sailing vessels carried away on shore. Slight damage to light structures situated near coast. In estuaries reversal of river flow for some distance upstream.

IV

4

Strong

Flooding of the shore to some depth. Light scouring on man-made ground. Embankments and dykes damaged. Light structures near the coast damaged. Solid structures on the coast slightly damaged. Big sailing vessels and small ships drifted inland or carried out to sea. Coasts littered with floating debris.

V

8

Very strong

General flooding of the shore to some depth. Quay walls and solid structures near the sea damaged. Light structures destroyed. Severe scouring of cultivated land and littering of the coast with floating items and sea animals. With the exception of big ships all other types of vessels carried inland or out to sea. Big bores in estuary rivers. Harbour works damaged. People drowned, waves accompanied by strong roar.

VI

16

Disastrous

Partial or complete destruction of man-made structures for some distance from the shore. Flooding of coasts to great depths. Big ships severely damaged. Trees uprooted or broken by the waves. Many casualties.

Volcanic explosivity index (VEI)

Volcanic intensity

Tsuya scale

Eruption rate (kg/s)

Volume of ejecta (m³)

Eruption column height (km)

Thermal power output (log kW)

Duration (hours of continuous blast)

0

V

I

10²-10³

<10⁴

0.8-1.5

5-6

<1

1

VI

II-III

10³-10⁴

10⁴-10⁶

1.5-2.8

6-7

<1

2

VII

IV

10⁴-10⁵

10⁶-10⁷

2.8-5.5

7-8

1-6

3

VIII

V

10⁵-10⁶

10⁷-10⁸

5.5-10.5

8-9

1-12

4

IX

VI

10⁶-10⁷

10⁸-10⁹

10.5-17.0

9-10

1->12

5

X

VII

10⁷-10⁸

10⁹-10¹⁰

17.0-28.0

10-11

6->12

6

XI

VIII

10⁸-10⁹

10¹⁰-10¹¹

28.0-47.0

11-12

>12

7

XII

IX

>10⁹

10¹¹-10¹²

>47.0

>12

>12

8

-

-

-

>10¹²

-

-

>12

Class 1 - Explosives

-

-

Class 2 - Gases: compressed, liquefied or dissolved under pressure

Class 2.1

Flammable gases

Class 2.2

Non-flammable non-toxic gases

Class 2.3

Toxic gases

Class 3 - Flammable liquids

Class 3.1

Liquids with a flashpoint below -18°C (closed cup test)

Class 3.2

Liquids with a flashpoint of -18°C up to but not including 23°C (closed cup test)

Class 3.3

Liquids with a flashpoint of 23°C or more, up to and including 61°C (closed cup test)

Class 4 - Flammable solids

Class 4.1

Flammable solids

Class 4.2

Substances liable to spontaneous combustion

Class 4.3

Substances which emit flammable gases on contact with water

Class 5 - Oxidizing substances(agents) and organic peroxides

Class 5.1

Oxidizing agents

Class 5.2

Organic peroxides

Class 6 - Toxic and infectious substances

Class 6.1

Toxic substances

Class 6.2

Infectious substances

Class 7 - Radioactive substances

-

-

Class 8 - Corrosives

-

-

Class 9 - Miscellaneous dangerous substances and articles

-

-